The compound 2,6-diamino-3,5-dinitrotoluene (“DADNT”) (I),
may be used as a starting material or intermediate in the preparation of a variety of products, which include dyes, pharmaceuticals, and monomers for incorporation into polybenzimidazole polymers.
The preparation of DADNT has been reported by J. J. Blanksma, in “Nitro Derivatives of 2,6-Dibromotoluene,” Chemisch Weekblad 9, 968-973 (1913). The starting material was 2,6-dibromotoluene, which was dinitrated and reacted under pressure with NH3 at 150° C. This process has limited commercial viablity because of the high cost of 2,6-dibromotoluene. Furthermore, the brominated intermediates produced in this process are highly skin sensitizing chemicals and would not allow for low cost production in a commercial setting because of environmental and handling issues.
High purity DADNT is useful as a precursor to high-purity 2,3,5,6-tetraaminotoluene (“TAT”) (Formula II),
which may be used as a precursor to high-performance polymers such as polybenzimidazoles, which are used to make high-performance, high-strength fibers. The purity of the precursors affects the polymer molecular weight that can be achieved, which in turn determines whether satisfactory fibers can be produced.
A need thus remains for a process for making 2,6-diamino-3,5-dinitrotoluene with higher selectivity and purity.